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UNITED STATES;

STEPHEN 1;. GOODALE, OFSACQMAINE, ASSIGNOR 'ro ALFRED Mcooimil [PATENT came,

or WALT-HAM, MASSACHUSETTS, AND MARCIA, W. A. s mmer, on roar- LAND, MAINE, TRUSTEES.

METHOD OF TREATING HYDRATED, PHOSPHATES OF AYLUMINAJQJQ:

SPEOiFIGATIQN forming part of LettersPatentNo. 493,889,.datedMarch- 21,;1893. Application filed February 21, 1889. Serial No. 300,754. (No specimens.) i i J To aZLw'hom it may concern. i 7

Be it knownthat I, STEPHEN L. GOODALE,

a citizen of the UnitedStates, and a resident of gSaeo, in the county of York and State of Maine have invented or discovered acertain new and useful arts of and improvement in treating hydrated phosphates of alumipa or of iron or both for the purpose of convert-lv ing them-into. fertilizer or plant food" of imxo proved properties and. increased value; and

I do hereby declarethat the following is a full, clear, and exact description 'of the invention, which will enable others skilled in the artto which. it appertains to'make and I5 use the same. I

; My discovery and inventionrelate to manufacturing'aplantrfood or concentrated fertilizer,-from insolublehydrated phosphates of alumina and of iron, whose large contents of '20 phosphoric acid, essential to plant growth,

become accessible to plants in nature only as slowly disintegrated by weathering. My discovery i's, broadly, that heat alone can be so applied as to produce such a ehange in these phosphatesas to render them readily citrate soluble oonnnonlycallejd available and assimilable by plants; andthat to reach this result, heat must be sufiicientto expel the com? bined water, and must notlbe so great as-to 3o disturb the organizationor constitution thus brought about. The product thusreachcd is a different fertilizer from previous products (because free from dilution or adulteration by chemicals as oceursuudcr other processes) and is abctter fertilizer because furnishing more available-.phosphorie acid, and is a cheaper fertilizer to manufactu re and to transport.

My invcntion-based upon my said discov- 40 eries-coi 1sists in aprocoss or method of renderingdhese phosphates available as fertilizers.

The scope and practice of my discovery and invention will be more readily understood by l referenceto thestate of the artof manufac- V turingsuchplantfood. It is well knownthat plantsabsorb phosphoric acid from the soil and grow thereby, and the value of fertilizer from these phosphates depends upon their large 5o amount of phosphoric aeid being rendered :readilyassimilable by plants. Hitherto these? 1nax muurof phosphoric acid available r vcrude phosphates have been rendered fit for plant food only by aid ofsome second substance. The sulphuric acid proeessfor manu} facturing fertilizer from phosphatesof lime, h;

can not be used with these phosphates But? treatment with. other chemieals-mi1riatic acid, eausticlime, soda and potash sulphates and other ,re-agent,s- -or; mechauieal miiv g v with less aetiveisubstances, hayebeen prac-c tieed. all these pro- Practical 1y, howeveri cesses have been but partially successf ul,;i'n

volving dilution, or excessiveeost; and only oeeasionallyvand accidentally rendering the Under my discovery and iliventio nl doj fl not only rendermore phosphoric acid avail-f table and morespeedily so, but I do it without the expense or the aidof-an y second material,

and I obtain a-diiferent a cheaper, and a hetter plant food. 1 have been led: by a long course of experiments to my discovery which? is two-fold; first that plants can readily and i rapidly assimilate or convert the phosphoric acid of: these phosphates from their residuum 7 5i, alone just as it is left after eliminationby 1. .heatof the .water of constitution; and sec? pndly that such residuum can be obtained by properly applying onlysuch definite amount" of heat as not to develop nnfavorably molecuso vlar rearrangement, or, if this can not be considered a demonstrable statement, as not to impair this condition of solubility; inasmuch as heat in proportion as it goes beyond the requisite amount, is sooner or-later destructive 8 of the desired solubility and assimilztbility of the residue. 1

My process of manufacturingthis plant food or fertilizer based upon the foregoingdiscoverics will be seen to be not only simple o and certain, butdistinct from prioi'processes whether successful or unsuccessful. None of the steps, in and of themselves which Itake with the crude material, are novel, although they are entirelyso as to the rules by which 5 they are taken,and as applied to this subject matter, and for this purpose. For instance,

it has longbeen knownwthat in determining a chemical constituents byoanalysisg Water: or

other volatile elements maybeeliminatedby whereby its solubility j on the gold surface as means of heat, as is sometimes expressed'by the word calcining. But my process consists essentially in so applying heat and limiting its amountthat while the combined water shall, be" entirely expelled no injury shall be done to the residue by excess of heat, is impaired. My manufacturing process then is comparatively simple. There must be a suitable heating receptacle' for theraw material, having a vapor outlet; It must be so constructed that the heat will be admitted and distributed uniformly. Ordinary methods of controlling the heat will be found necessary Heat must not be applied directly, as by an incandescent material or flame coming in contact with the phosphate. The heat must be applied within limits which, although somewhat variabl'e, are quite determinable. 'lhis variability arises mainly from three sources, first, dittering proportions of iron or alumina in different samples of the phosphates; second varying degrees of hydration ranging from sixteen per cent. (or occasionally below) to twenty-five per cent. and third, the presence of accidental or indifferent matters containing no combined water. Tests in a small way may determine this for given lots.

In most casesthe proper effect of the heat will be secured at about 325 .centigrade. more exactly determine the necessary amount of heatin any given case by exposing from time to timc,as the heat approaches 275 centigrade, a metallic or other proper cold surface to the orilice where escaping invisible vapor, can be recognized by being deposited posit ceases f urthor increase of heat must be arrested lest the condition of solubility be destroyed. So'far as this is a'variable rule, it is at the same time definite, inasmuch as ialthougliit describes noabsolute fixed temperature, it yet contemplates variation in the rule only as the crude samples vary.. lleat to the requisite amount having'been thus applied its further increase is arrested. quantities are to be treated at one operation great care should begivcn in regard to continuance and especially to increase of heat near the end, in order to avoid over-passing (or occasionally above) dew, and when this de It large the proper limit. This is especially needful for an operator before he has acquired cient practical familiarity with the manipulation appropriate to phosphates, and which should allow for the continuance of heat after the drafts have been closed. These rules will be found complete, satisfactory and successful; although there may be variations in the raw material other than what I have noticed. In my experience the water of constitution in different samples varies, as I have iutimated;'

about 275 appeared to be the maximum of pics, andv from that to 325 centigrade for samples having the maximum water of constitution.

Ilavingthus explained my discoveries and described the way in which they are to be applied in the new process by means of heat alone by which means for the first time not only has a fertilizer or plant food but a different and better one been obtained from these phosphates, I should not wish to be understood as claiming broadly the chemical procedure which chemist-s have for many years termed dehydration, nor of course the process of calcining without reference to speciiic subject matter and under specific rules,

centigrade has but What I do desire to protect by Letters Patout and claim is-- The new art or process of renderinginsoluble hydrated phosphates otalumina and of iron easily soluble and so available as rapidly which consists in heatacting plantfertilizers, ing these phosphates, in suitable receptacles, by the indirect application of heat, until all the water of constit ition is expelled, or usually, until heat has een applied suilicient to raise the temperature of the mass to about 325 centigrade, and then arresting the heat and allowing the resulting productto cool spontaneously, substantially as and for. the purpose described.

In testimony whereot I have hereunto subscribed my name this 20th day of February, A. 1). ms.

S'lElllEN I. GO'ODALE.

Witnesses:

JonN ll. TAYLOR, ELLEN l). 'lOltiLINSON heat for the least hydrated sam 

